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NOTES � iR�\ I �jj n���rmm� <br /> 1. aR$EM4P FROM SURVEY LONOIIOIID BYMORROW � \\�//1 CS"l <br /> SIIRVEYINa OF WESTSACRPMEMO,CALIFIXWIA p�MTEUAPRIl2 R00B. I Y1at r Boards v u <br /> 1STmHuamY.,41:— <br /> Central Valley Regional Water Quality Control Board <br /> 1 XRA�,.NEv�p..l <br /> 29 April 2020 <br /> Tim Cosgrave -- <br /> Director,Environmental. Health R Safety <br /> UniFirst Corporation <br /> 68 Jorlspin Road <br /> Wilmington, MA 01887-1090 <br /> fyStREET <br /> FFAST pOP� &13 &12 CONDITIONAL CONCURRANCE WITH REVISED INTERIM REMEDIAL ACTION <br /> 1 WORKPLAN,UNIFIRST,819 HUNTER STREET,STOCKTON,SAN JOAQUIN <br /> 1 COUNTY <br /> Staff of the Central Valley Regional Water Quality Control Board(Central Valley Water <br /> Mwnae , Board)haver reviewed the 17 April 2020 Interim Remedial Action Work Plan—Revision <br /> k�-10G 1 1 2(Workplan Revision 2),submitted on your behalf by Wood,PLC. Unifirst operates a <br /> wet wash laundry service at a site that had previously been operated as a dry cleaner. <br /> 1 201 The drycleaning agent Perchlorcethene(PCE)is found in groundwater beneath the <br /> A 1 facility. <br /> 1 = UniFirst has been conducting monitoring and cleanup activities for PCE and its <br /> degradation product Trichlorcethylene(TCE)at the Site utilizing subsurface injections of <br /> 9� 5V `� 4 We Mw,H 1 7� Hydrogen Releasing Compound(HRC),which promotes microbial degradation of these <br /> A, WIA 1n <br /> '¢ (G 1 chemicals. Wood previously submitted the 4 January 2020,2019 Interim Remedial <br /> eo'b� 1 y Action Work Plan—Revision 1 to the Regional Board to propose addition subsurface <br /> injections to enhance the continued breakdown of the PCE and TCE.Regional Board <br /> staff requested an additional revision that included measures to assess the width of the <br /> groundwater plume to support new monitoring well and injection location selections.$ <br /> 4 P Q 1 1 The Workplan Revision 2 calls for advancing two soil vapor borings near the <br /> 3 intersection of East Poplar Street and North Hunter Street,Those soil vapor samples <br /> 1 1 will be collected to determine appropriate placing of a new duster of monitoring wells <br /> nearby,referred to as MW-10. <br /> 1 1 The Workplan Revision 2 proposes injection using 3-D Microemusion(3-DME), <br /> 1 Chemical Reducing Solution(CRS),Bio-Dechlor Inoculum Plus(BDI)instead of HRC to <br /> support reductive dechlorination because remediation technologies have improved. <br /> F 3-DME will therefore be used for this injection,as discussed in the Workplan. <br /> ? i cr.F:NO Regional Board staff discussed the Workplan and the need to delineate the northern <br /> x boundary of the plume with Mr.Bill Aravanis of Wood plc on 24 April 2020.Therefore, <br /> g "^`f6� pioposo°MI'"bnWe0�0on Proposed Injection Well,Monitoring Well, the Regional Board concurs with the Workplan,with the following stipulations: <br /> and Soil Vapor Boring Locations <br /> S O MWSB EdMbp MOFIRR p WE, UniFlat Facility IGRL E.LONOLc SCc,P.E..crwn I PATRICK PnLaPA,ECO.,EXECUTIVE OFFICER <br /> SIOOdion,California <br /> ® work Arx "tC.3m GnGr RIw RM,MneRE.. X,CA... I —.KAE—..R—, .nK...1, <br /> 2 Xr 12 ShcVepr SOTOODON a.J3$ I CENI:0L1 o37yppd, ID 8 <br />